A run-away preventing device having a rotatably supported holding bar and a cross support which lies perpendicularly with respect to the longitudinal axis of the ski is already known, the two wings of said cross support being arranged on the sides of the ski. This run-away preventing device can be rotated under spring action into a braking position, in which the wings project substantially vertically from the ski downwardly, and in which the wings are hinged on pins which in turn are mounted on the sides of the ski. One or more tension springs are secured at one end on the wing and at the other end eccentrically on the pin. Such ski brakes are expensive and the operation of the springs can be easily affected by outside influences like ice, dirt, snow, dust and the like.
Further, the market already offers a ski brake provided with a multiple-wound spring wire. The ends of the spring wire form herein the brake legs and the wound portion, mounted on the ski under a plate, form in effect, due to their sloped position, torsion springs which are not greatly subject to external influences. However, it is not possible in a simple manner to increase the strength of the brake legs by increasing the spring wire dimension, because then the spring force also becomes too great and in the condition of use wherein the spring legs are held in an upwardly swung position by the ski boot, the force of the ski brake onto the ski boot becomes excessive. Thus, this run-away preventing device is limited in its dimensions.